1. Field of the Invention
The present invention relates to an antenna structure, and more particularly, to an antenna structure comprising a fixing unit. The fixing unit is in contact with a signal transmission unit and a hole of a substrate to fix the signal transmission unit on the substrate.
2. Description of the Prior Art
Please refer to FIG. 1. FIG. 1 is a diagram illustrating a typical patch antenna 100. As shown in FIG. 1, the patch antenna 100 includes a substrate 110 and a metal stick 120. The substrate 110 is made of a dielectric material, such as ceramic. The top surface and the bottom surface of the substrate 110 are both coated with metal to act as a radiation electrode 112 and a ground electrode 114 respectively. In addition, the substrate 110 also has a through hole 116. The metal stick 120 is disposed in the through hole 116 to connect the radiation electrode 112 with a signal processing device (not shown in FIG. 1).
However, a slight difference in the relative position of the metal stick on the substrate may result in variations in antenna characteristics, such as resistance, frequency, and the degree of circular polarization. Therefore, in the mass production of patch antenna, the manufacturing variations of the inner diameters of the through holes and the outer diameters of the metal sticks, as well as the relative shifting of the metal position during assembly would result in a wide distribution in their characteristics.